The invention relates generally to graphical user interfaces for computer systems and, more particularly, to a graphical user interface element providing multiple levels of granularity for application control.
In general, a user interface is the means through which a user interacts with a computer system. Graphical user interfaces (GUIs) employ windows and icons in conjunction with a cursor control device. Most cursor control devices include a switch for generating signals to the computer system to indicate a selection or other user action. The combination of windows, icons, and a cursor control device permits a user to operate in a visual “point-and-click” manner. As used herein, the phrase “point-and-click” refers to positioning a cursor on a display so it is over a desired image and activating a switch (e.g., a button, a finger tap or a stylus tap) on the cursor control device. One illustrative graphical user interface is the Finder™ interface for the Macintosh family of computer systems. (FINDER is a trademark of, and MACINTOSH is a registered trademark of, Apple Computer, Inc. of Cupertino, Calif.)
Equipment and application controls have been simulated for display through a GUI. For example, graphical representations of a volume control knob and a visual zoom slider control are indicative of GUI elements used in today's graphical user interfaces. To adjust the application's settings (e.g., the playback volume, visual magnification or angle of image rotation), the user positions a cursor over the graphical representation of the knob or slider, activates the cursor control device by clicking and holding the cursor control device's button and drags the cursor in a circular or linear motion to achieve the desired setting (e.g., volume, rotation or zoom level).
While more convenient than a command-line input interface, conventional GUI elements only permit the user to adjust the desired parameter in a linear fashion. That is, when the user adjusts the GUI element through a specified range (e.g., 45 degrees rotation or 1 inch of liner motion), conventional GUI elements adjust the associated parameter (e.g., image rotation or volume) a corresponding specified amount. This can make it difficult for a user to rapidly change the target parameter through a large range while also permitting the user to finely adjust the parameter's final or end-value. For example, if a 2 inch slider is used to control the rotation of a selected image, a 1 inch change in the slider control's position will cause a 180 degree rotation of the displayed image. While this permits the user to rapidly adjust the image's rotation through a wide range, the resolution of the GUI element can make it difficult to precisely control the final value.
Thus, it would be beneficial to provide a GUI element that permits a user to rapidly adjust an application's operation in a first (coarse) manner while also permitting the user to adjust the application's operation is a second (fine) manner.